scsi: st: New session only when Unit Attention for new tape

jira LE-2742
Rebuild_History Non-Buildable kernel-5.14.0-503.33.1.el9_5
commit-author Kai Mäkisara <Kai.Makisara@kolumbus.fi>
commit a4550b2

Currently the code starts new tape session when any Unit Attention
(UA) is seen when opening the device. This leads to incorrectly
clearing pos_unknown when the UA is for reset. Set new session only
when the UA is for a new tape.

	Signed-off-by: Kai Mäkisara <Kai.Makisara@kolumbus.fi>
Link: https://lore.kernel.org/r/20241106095723.63254-4-Kai.Makisara@kolumbus.fi
	Reviewed-by: John Meneghini <jmeneghi@redhat.com>
	Tested-by: John Meneghini <jmeneghi@redhat.com>
	Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
(cherry picked from commit a4550b2)
	Signed-off-by: Jonathan Maple <jmaple@ciq.com>

Author: PlaidCat

drivers/scsi/st.c

@@ -991,7 +991,10 @@ static int test_ready(struct scsi_tape *STp, int do_wait)
 			scode = cmdstatp->sense_hdr.sense_key;
 
 			if (scode == UNIT_ATTENTION) { /* New media? */
-				new_session = 1;
+				if (cmdstatp->sense_hdr.asc == 0x28) { /* New media */
+					new_session = 1;
+					DEBC_printk(STp, "New tape session.");
+				}
 				if (attentions < MAX_ATTENTIONS) {
 					attentions++;
 					continue;